1. THE EPIDEMIOLOGY OF
PHYSICAL ACTIVITY AND
NUTRITION IN AUSTRALIA
XNN001 Population nutrition and physical
activity assessment

2. Chronic conditions
internationally
 35% of adults over 20 years overweight, 12%
obese
 Global prevalence of diabetes estimated to be
10% in adults aged 25+ years (221 million
people)
 151 million with osteoarthritis
 64 million with chronic obstructive pulmonary
disease (symptomatic cases)
 54 million with angina pectoris
 31 million were stroke survivors

3. Chronic conditions in Australia
 28% of adults 18 years and over obese, 35%
overweight
 17 per cent of boys and girls overweight; 6 per
cent obese
 17% of the population have one or more long
term conditions of the circulatory system
 32% of the population have hypertension
 Chronic conditions account for 80% of the total
burden of disease

4. Chronic conditions and modifiable risk factors (AIHW,
2012)
4

5. Population-level dietary and PA
data in Australia
 Often collected as a component of broad
surveys (e.g. National Health Surveys)
 Changing measures and sampling methods-
limited evaluations of trends
 No systematic data collection

6. National Health Survey
 Alcohol consumption
 Fruit & vegetable intake
 Physical activity level
 Household food security

7. Nutrition Surveys in Australia
 National dietary surveys among adults-
1983, 1995, 2011-12
 Children’s surveys 1985, 1995, 2007
 Conducted by different agencies – different
sampling & data collection methods, different
food composition tables

8. Diet
 48% met recommendations for fruit
 9% met recommendations for vegetables
 ~ 5% meet recommendations for both fruit and
vegetable
 Total fat intake provided ~32% of energy
 SF 13% total energy (1995 NNS)
 <5% of households food insecure ((2004/05 NHS)

9. Diet children
 Low proportion meeting recommendations for
F&V
 Saturated fat intake high
 Intakes of some micronutrients high

10. Physical activity
 67% adults had sedentary or
low levels of physical activity
 66% of school children
participated in PA, however for
most this was less than 2 hours
per week
 95% of school children
participated in sedentary
leisure time activities, for most
this made up 10 – 19 hours

11. State-level data
 Differs by state
 QLD- no systematic approach to collecting
information about population diet and PA
 Qld Omnibus survey
 Qld cancer council risk study (2004)
 NSW & Vic- regular Population Health surveys

12. Extending beyond surveys of
individuals
 Food supply data
 Nutrient composition of foods
 Australian Household Expenditure Survey
 International comparisons

13. Food supply data
 To calculate ‘available food for consumption’ – Food balance
sheets
 Information on amounts of food (raw commodities)
available for consumption per year
Food available for use =
production + imports – exports
 Food available for consumption =
 production + imports – exports – industrial use – animal use
 Important – food available for consumption does NOT tell us
how much food is actually eaten!

14. Food supply data
 To compare food trends within Australia Apparent
food consumption data
Apparent consumption =
(commercial production + estimated home production +
imports + opening stocks)
(exports + usage for processed foods + non-food usage +
wastage + closing stocks)
MINUS

15. Tables of food composition
 Used to:
 Convert information about food intake to nutrient intake
 Contain:
 Nutrient data that is an average of nutrients in a particular
sample of foods & ingredients, determined at a particular
time
 Need to:
 Be current
 Match the food supply
NOTE: The nutrient composition of foods & ingredients can vary
substantially over different batches, & between brands because of a
number of factors including:
• Changes in season
• Processing practices
• Ingredient source

16. Limitations of food composition
tables
 Limitations:
 Food supply changes quickly
 Biological variation of foods
 Single values representing range
 Incomplete data – missing foods & nutrients
 Bioavailability not considered
 Potential measurement & data entry error
 Relate to food supply of that country

17. Food purchasing and acquisition
 Household food expenditure
 budget surveys
 provides data on amount of
money/proportion of income spent on food
by different kinds of households
 provides weighting figures for CPI
(Consumer Price Index)
 not measuring foods or nutrients

18. Population-based
recommendations
 Nutrient reference values (NRVs)
 Food-based dietary guidelines
 Physical activity guidelines-
children, adults, older adults

19. Nutrient Reference Values
 Retain the concept of the RDI
 Provide more complete information for decision
making about nutritional status of individuals and
groups
 Outline the levels of intake of essential nutrients
considered to be adequate to meet the known
nutritional needs of practically all healthy people
for prevention of deficiency states.

20. Nutrient Reference Values
 The document can be used by health
professionals to assess the likelihood of
inadequate intake in individuals or groups of
people.
 NRV is ‘umbrella term’, there are different NRV
values for different nutrients:
• EAR – Estimated Average Requirement
• AI – Adequate Intake
• RDI – Recommended Dietary Intake
• UL – Upper Limit of Intake
• EER – Estimated Energy Requirement
• SDTs – Suggested Dietary Target
• AMDRs – Acceptable Macronutrient Distribution

21. Nutrient requirements
 Developed using reference (standard) body
weights for different age groups
 Estimated Energy Requirements (EERs)
include physical activity level (PAL)
consideration but refer to standardised weight
for age
 Adults well above and below the reference
standard will have slightly different nutrient
requirements (use RDI)

22. Estimate Average Requirement –
EAR
 Daily nutrient level estimated to meet the
requirement of half the healthy individuals in a
life stage/gender group (ie median value)
 Uses:
Individuals: use to examine the probability that
usual intake is inadequate
Groups: use to estimate the prevalence of
inadequate intakes within a group

23. Recommended Dietary Intake -RDI
 Average daily dietary level sufficient to meet the
nutrient requirements of NEARLY ALL (97-98%)
healthy individuals in a life stage & gender group
 Uses:
Individuals: usual intake at or above this level has a
low probability of inadequacy
Groups: DO NOT USE TO ASSESS GROUPS

24. Adequate Intake – AI
 Average daily intake based on observed or
experimentally-determined approximations or estimates
of nutrient intake by a group of apparently healthy people
that are assumed to be adequate
 Used when an RDI can not be determined
 Uses:
Individuals: can be used as a goal for individual intake
but use with caution if nutrient level is based on median
intakes of healthy populations
Groups: if mean intake is at or above this level, a low
prevalence of inadequacy is likely

25. Upper Limit – UL
 Highest level of continuing daily nutrient intake
likely to pose no adverse health effects in almost
all individuals
 Uses:
Individuals: usual intake above this level may place
an individual at risk of adverse effects from
excessive nutrient intake
Groups: use to estimate the % of the population at
potential risk of adverse effects from excessive
nutrient intake

26. Summary of the uses for the
NRVs
NRV Individuals Groups
EAR Use to determine probability usual
intake is inadequate
Use to estimate prevalence of
inadequate intakes within group
RDI Usual intake at or above this level
has a low probability of inadequacy
DO NOT USE TO ASSESS
INTAKES OF GROUPS
AI Usual intake at or above has a low
probability of inadequacy. When AI
is based on median intakes of
healthy population, interpret with
caution.
Mean usual intake at or above this
level implies a low prevalence of
inadequate intake. When AI is
based on median intakes of healthy
population, interpret with caution.
UL Usual intake above this level may
place individual at risk of adverse
effects from excessive intake
Use to estimate % of population at
potential risk of adverse effects from
excessive nutrient intake

27. Dietary Guidelines 2013
(NHMRC)
 Recommendations (‘guidelines’) which
encourage healthy lifestyles that will minimise
the risk of the development of diet related
diseases within the Australian population
 Highlight the groups of foods and lifestyle
patterns that promote good nutrition and health
 Available in ‘Eat for Health’ publication

30. Dietary Guidelines 2013
 Focus on:
 Contribution of core foods & major sources of
energy (fat, starch & sugar) to the overall diet
 Provide:
 A practical way of informing consumers about food
choices that are consistent with current dietary
recommendations
 Separate guidelines for adults and children &
adolescents

31. Dietary guidelines 2013
 Outlines how many
serves a person
should have of
each food group
based on their:
 age
 gender
 body size (to a
degree)
 activity level (to a
degree)
 Provides examples

32. Dietary Guidelines 2013
–
notes for use
 Summarise current nutrition knowledge
 Trigger more comprehensive education
programs
 Represent best consensus of scientific
knowledge
 For use by healthy adults
 Apply to whole diet not to individual
foods
 Guidelines are meant to be
complementary not separate items
 Not appropriate for cross cultural issues
or unusual habits

33. PA recommendations
Australia’s Physical Activity Recommendations for 5-12 year olds
 For infants (birth to one year) physical activity – particularly
supervised floor-based play in safe environments – should be
encouraged from birth.
 Toddlers (1 to 3 years) & Pre-schoolers (3 to 5 years) should be
physically active every day for at least three hours, spread
throughout the day.
 Children younger than 2 years of age should not spend any time
watching television or using other electronic media
(DVDs, computer and other electronic games) and for children 2 to
5 years of age these activities should be limited to less than one
hour per day.
 Infants, toddlers and pre-schoolers should not be
sedentary, restrained, or kept inactive, for more than one hour at a

34. PA recommendations
Australia’s Physical Activity Recommendations for 5-
12 year olds
 Children need at least 60 minutes (and up to several
hours) of moderate to vigorous physical activity every
day;
 Children should not spend more than two hours a day
using electronic media for entertainment (e.g.
computer games, TV, Internet), particularly during
daylight hours.
Australia’s Physical Activity Recommendations for
12-18 year olds
 -12-18 year olds should be doing at least 60 minutes
of moderate to vigorous physical activity every day to
keep healthy;

35. PA recommendations
National Physical Activity Guidelines for
Adults
 Think of movement as an opportunity, not an
inconvenience;
 Be active every day in as many ways as you
can;
 Put together at least 30 minutes of moderate-
intensity physical activity on most, preferably
all, days;
 If you can, also enjoy some regular, vigorous
activity for extra health and fitness.

36. PA recommendations
Recommendations for Physical Activity for Health for Older
Australians
 Older people should do some form of physical activity, no matter
what their age, weight, health problems or abilities;
 Older people should be active every day in as many ways as
possible, doing a range of physical activities that incorporate
fitness, strength, balance and flexibility;
 Older people should accumulate at least 30 minutes of moderate
intensity physical activity on most, preferably all, days;
 Older people who have stopped physical activity, or who are
starting a new physical activity, should start at a level that is easily
manageable and gradually build up the recommended amount,
type and frequency of activity;
 Older people who continue to enjoy a lifetime of vigorous physical
activity should carry on doing so in a manner suited to their
capability into later life, provided recommended safety procedures
and guidelines are adhered to.

37. Measurement issues
 Error- validity
 when an estimate
(eg, incidence, prevalence, mortality) or association
(RR, OR) deviates from ‘true’ situation in nature
 May be introduced at any point during the
study:
Study design (quality)
sampling
Measurement
Analysis
Random error
Systematic bias

38. Random error
 Fluctuations around a true value
 Related to poor precision
 Sources
individual biological variation (always present)
 sampling variation
measurement variation (protocols and training)
 Reduced by:
 larger sample sizes
 standard protocols and equipment

39. Systematic bias
 Any systematic error in the design, conduct
or analysis of a study that results in a
mistaken estimate of an exposure’s effect on
the risk of a disease
 Due to causes other than random error
 Problem of validity
 internal and/or external validity